The Mercedes-Benz C111 was a series of experimental automobiles produced by Mercedes-Benz in the 1960s and 1970s. The company was experimenting with new engine technologies, including Wankel engines, diesel engines and turbochargers, and used the basic C111 platform as a platform of test. Other experimental features included multi-link rear suspension, gull-wing doors and a luxurious leather-trimmed interior and air conditioning.

The first version of the C111 was completed in 1969. The car used a fiberglass body and a three-rotor direct injection Wankel engine with intermediate assembly (code name M950F). The next C111 appeared in 1970. It used a four-rotor engine producing 257 kW (350 hp). The car would have reached a speed of 300 km / h (186 mph).

The company decided not to adopt the Wankel engine and turned to Diesel experiments for the second and third C111. The C111-IID produced 140 kW (188 hp) and was based on the OMD16 240D 3.0 W115 engine.

The C111-III was equipped with a 4.5 kW (228 hp) and 4,500 rpm OM617 turbocharged engine, which broke nine diesel and gasoline speed records. With a more aerodynamic body that gave it an aerodynamic coefficient of 0.161, the C111 eventually reached 320 km / h on the Nardò Ring in 1978, and an average of 16.0 liters / 100 km at 316 km / h (14.7 mpg at 195, 4 mph) over a 12-hour cruise.

The latest 37 K kW V8 version with a 372 kW (500 hp) turbocharger set another record, with an average lap speed of 403.78 km / h (250,958 mph). This was achieved by Hans Leibold in 1 minute, 56.67 seconds on May 5, 1979. The total production was 16 cars: 13 first and second generation Wankel engine cars, 2 used third generation diesel cars Attempting to record Nardo, and a single V8 with fourth generation engine.